This summary and update is for the mercury release at the Walter Johnson Middle School, in Las Vegas, NV. At about 12:00 on Wednesday (9/7/16), Las Vegas Fire & Rescue personnel contacted EPA’s Environmental Response Team (ERT) in Las Vegas to request technical assistance with screening several students for possible mercury contamination. ERT notified the Region 9 Phone Duty Officer prior to their departure to the school and followed up with a call describing the mercury levels measured at the school by ERT, based on these levels OSC Nattis deployed to the release on Wednesday afternoon. Upon arrival at approximately 9:30 PM OSC Nattis adjusted the system for screening students who were being held by the school district, and implemented contamination control zones to prevent further cross contamination, which had been problematic aspect of the screening process until then. All 1200+ students were released by approximately 4:30 AM Thursday. Approximately 80 students received some degree of decontamination including: 4-5 girls who had to have her hair washed and blow dried, some more than once; several boys with contamination on their chest and arms requiring full shower decontamination; several using wipes and solutions on their arms; and, the remainder requiring washing hands or feet. All decontamination was administered by Las Vegas Fire & Rescue personnel. The personal belongings of each student were also placed in black garbage bags with the students ID distinguishing each bag.
At 10:00 AM Thursday (9/8/16) a press conference was held and led by Clark County School District (CCSD). Also on Thursday EPA began screening the head space of the black garbage bags. As of mid-day Friday (9/9/16) approximately one third of the 1200+ bags have been screened and while most bags are showing relatively low levels of mercury (below 3000 ng/m3), approximately 49 bags have shown mercury contamination in the head space at or above 50,000 ng/m3, which is a level more indicative of gross mercury within the contents of the bag. Additionally approximately 40 bags of items have been brought to the school from homes for screening, and 9 of these had head space reading above 50,000. The school district is preparing to contact the homeowners corresponding to bags with significant elevated head space readings, to arrange for EPA access and screening of the respective homes. The total number of homes which could receive indoor mercury screening could potentially be as high as 200.
Based on the findings of the indoor screening effort, some homes could require the removal of contaminated material such as clothing, carpet and other material which cannot be decontaminated in place. The CCSD has retained a local clean up contractor who is proceeding with clean-up of the school starting with the gymnasium and locker rooms which are the most heavily contaminated.
On Thursday evening a community open house was held to address questions and concerns of parents. More than 300 people attended. The source of the mercury has not be ascertained but it is widely held that the initial release occurred at least 5 days (sometime prior to the Labor Day weekend) before its discovery Wednesday. The CCSD Police Department is reviewing available security camera footage from the school.